Transplants: Natural v. Artificial Hearts

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When surgeons began boldly transplanting human hearts, they appeared to come into direct competition with researchers who had spent years trying to devise an artificial heart. But last week Houston's Dr. Denton A. Cooley, who has transplanted more hearts than any other surgeon, brought the two lines of investigation into a neat, complementary fit.

Transplants, Cooley told an American College of Cardiology meeting in Los Angeles, have produced evidence that the development of a successful artificial heart "may actually be easier than we had previously believed." The explanation: nature has provided the mammalian (including the human) heart with an elaborate fail-safe system of dual controls, one through the nervous system and another through hormonal channels. Early researchers on artificial hearts were overwhelmed by the difficulties of trying to duplicate these enormously complex natural systems. This, said Cooley, is not necessary.

Responsive Enough. The transplanted heart has no connections with the brain, Cooley pointed out, and therefore cannot respond to nervous stimuli that, for example, make the normal heart beat faster when a person is excited. Yet although the transplanted heart is less sensitive, it is able to keep the recipient alive and is responsive enough to permit him a reasonable degree of activity. An artificial heart, Cooley suggested, need do no more. Artificial heart research, which will surely benefit from the knowledge gained by transplants, may in turn help to explain why the natural heart, with no connection to the brain, can begin pumping as soon as it is attached to the recipient's major blood vessels.

How soon will artificial hearts—or even temporary assist devices to do the work of the main pumping chamber—become generally available? That is still problematical. The University of Utah's Dr. Willem J. Kolff, inventor of the artificial kidney and an early artificial heart researcher, complained in Los Angeles that cardiologists are reluctant to try the devices "because anything artificial is looked upon with suspicion." He predicted that physicians would revise their thinking when they realize that the familiar heart drugs, in which they put great confidence today, cannot save patients whom an artificial heart might keep alive. But until man-made devices come along, Cooley intends to continue with transplants.